feat(worker): use TDLib remote.unique_id as zero-false-positive dedup signal

The fileName + size repost detection from ff4e150 works but has a
theoretical false-positive: two unrelated files in the same channel
with identical names and identical total sizes get treated as duplicates.

TDLib's document.remote.unique_id is a stable identifier per file
content — every repost of the exact same file across messages keeps
the same unique_id. Using it as the first dedup check eliminates the
false-positive risk entirely.

Schema:
  - Package.remoteUniqueId (nullable, since existing rows lack it)
  - Index on (sourceChannelId, remoteUniqueId)

Pipeline:
  1. Capture remoteUniqueId in getChannelMessages + getTopicMessages
  2. Pass through TelegramMessage type
  3. processOneArchiveSet checks findPackageByRemoteUniqueId FIRST
     (before packageExistsBySourceMessage / findRepostedPackage)
  4. createPackageStub stores it on the new Package row

Existing 19,952 Packages have remoteUniqueId = NULL — they fall through
to the existing checks (source-msg-id, name+size, content-hash). New
ingestions populate it and benefit from the strong signal immediately.
Old Packages get backfilled organically when their content is
re-encountered and a new Package would otherwise be created.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

worker/src/worker.ts

@@ -32,6 +32,7 @@ import {
   deleteSkippedPackage,
   getCappedSkippedMessageIds,
   findRepostedPackage,
+  findPackageByRemoteUniqueId,
   getRetryableSkippedMessageIds,
   updatePackageTopicContext,
 } from "./db/queries.js";
@@ -1240,6 +1241,38 @@ async function processOneArchiveSet(
 
   const archiveName = archiveSet.parts[0].fileName;
 
+  // ── Earliest skip: remote.unique_id match ──
+  // TDLib reports a stable unique_id per file content. If we already have a
+  // Package in this channel with the same unique_id, it's the exact same
+  // file content reposted at a new message ID — zero false positives.
+  const firstRemoteUniqueId = archiveSet.parts[0].remoteUniqueId;
+  if (firstRemoteUniqueId) {
+    const match = await findPackageByRemoteUniqueId(channel.id, firstRemoteUniqueId);
+    if (match) {
+      counters.zipsDuplicate++;
+      accountLog.info(
+        {
+          fileName: archiveSet.parts[0].fileName,
+          sourceMessageId: Number(archiveSet.parts[0].id),
+          remoteUniqueId: firstRemoteUniqueId,
+          existingPackageId: match.id,
+          existingDestMessageId: match.destMessageId ? Number(match.destMessageId) : null,
+        },
+        "Skipping — remote.unique_id matches an existing Package in this channel"
+      );
+      await updateRunActivity(runId, {
+        currentActivity: `Skipped ${archiveSet.parts[0].fileName} (already ingested by unique_id)`,
+        currentStep: "deduplicating",
+        currentChannel: channelTitle,
+        currentFile: archiveSet.parts[0].fileName,
+        currentFileNum: setIdx + 1,
+        totalFiles: totalSets,
+        zipsDuplicate: counters.zipsDuplicate,
+      });
+      return null;
+    }
+  }
+
   // ── Early skip: check if this archive set was already ingested ──
   // This avoids re-downloading large archives that were processed in a prior run.
   const alreadyIngested = await packageExistsBySourceMessage(
@@ -1705,6 +1738,7 @@ async function processOneArchiveSet(
         sourceChannelId: channel.id,
         sourceMessageId: archiveSet.parts[0].id,
         sourceTopicId,
+        remoteUniqueId: archiveSet.parts[0].remoteUniqueId ?? null,
         destChannelId,
         destMessageId: destResult.messageId,
         destMessageIds: destResult.messageIds,